flat bed puzzel

I have just about finishing part one of my TTT I have a new problem.
My trailer will seporate at the middle the lower part is a flat bed trailer looking something like this
I could run staps over the upper body of the trailer like you see them do with flat bed trucks.
I was thinking of some sort of latch. The walls are made of 2x4 pine I do have metal in the middle like the spine on a human.
I have thought of spring latches, ties from base of floor of upper body to trailer.
It is called the Box Kite so I could use heavy colored Rope and make it look like it is part of the image (going over the top and running town to the tung).
I probably have confused you as usual for me but I am a loss for words to explain it any farther.
I have pictures but am having technical difficulties and can not get them into this computer (working on it) to show you yet.
Ron Dickey The Box Kite Kid.
My trailer will seporate at the middle the lower part is a flat bed trailer looking something like this

I could run staps over the upper body of the trailer like you see them do with flat bed trucks.
I was thinking of some sort of latch. The walls are made of 2x4 pine I do have metal in the middle like the spine on a human.
I have thought of spring latches, ties from base of floor of upper body to trailer.
It is called the Box Kite so I could use heavy colored Rope and make it look like it is part of the image (going over the top and running town to the tung).
I probably have confused you as usual for me but I am a loss for words to explain it any farther.
I have pictures but am having technical difficulties and can not get them into this computer (working on it) to show you yet.
Ron Dickey The Box Kite Kid.